Boat hull construction



Dec. 30, 1947.

H. DITCHBURN BOAT HULL CONSTRUCTION Fiied Feb. 9, 1945 2 Sheets-Sheet 2 'A @En 7-A Inl/anion Wham Patented Dec. 30, 1947 BOAT HULL CONSTRUCTION Herbert Dtchburn, Trenton, Ontario, Canada This invention relates to improvements in steel boat construction and particularly a welded hull structure for speed boats, iiying boats, aeroplanes,

' military and other pontoons and commercial or work boats, and the principal object of the .n-f

vention is to produce a hull structure with an extraordinarily high strength, weight ratio at extremely low cost.

A further object is to devise a form of construction which will obviate the necessity of pro" viding moulds or setting up jigs and other expensive equipment usually required for fabricating steel in the conventional manner.

A still further object is to devise a construcstrengthening elements at various places in a hull structure without requiring special patterns and the shaping of transverse frames.

The principal feature of the invention consists in forming the longitudinal keel, chine and gunwale members of the boat of continuous lengths of tubing and spacing and rigidly connecting said longitudinal members with rigid struts having their ends abutting and securely welded to the longitudinal members, the outer shell plates of the hull being rigidly secured to said longitudinal tubes and transverse strut members.

A further feature of the invention consists in the novel arrangement of spaced longitudinalmembers for supporting the shell plates between the angularly disposed struts, whereby dishing or buckling of the plates will be prevented.

In the accompanying drawings,

Figure l is a half plan view of the frame of a speed boat constructed in accordance with this invention.

Figure 2 is a side elevational View of the boat hull illustrated in Figure lshowing the shell plates partly broken away at the bow end and showing the arrangement of the side struts in dotted lines. i'

Figure 3 is a half front elevational View of a boat hull frame structure showing a half sectional and rear end view..

Figure 4 is an enlarged horizontal sectional view taken throughthe stem portion of a boat frame constructed in accordance with this invention.

Figure 5 isV an enlarged half transverse broken section taken on the line 5-5 of Figure 2.

Figure 6 is an elevational detail of one of the side strut members as shown inthe assemblt7 of Figure 5.

Figure 7 is a broken longitudinal planV section Application February 9, 1945, Serial No. 577,032

2.Claims. (Cl. 9-6) 2 of a length of a boat hull taken on the line '1 v of Figure 5.

Figure 8 is a plan detail showing two different forms of metal longitudinal shell plate supports.

Figure 9 is a half sectional end elevational view showing a modified form of tubular hull construction particularly adapted for work boats.

In the manufacture 0f speed boats, flying boats and aeroplane hulls it has been customary to construct rigid ,transverse frames to be located at various points throughout the length of the non which win enable the placing of additional hull and to which the longitudinal planking is secured. Such construction is expensive and in order to have sufficient strength to stand the impact blows to which it is subjected in rough waters at high speeds the weight ratio is undesirably high.

The present invention contemplates the use of light but strong steel tubing to form the major longitudinal members of the boat structureand such structures are rigidly joined by light but strong metal struts to which an outer shell of light 'steel plating is rigidly secured by being welded at numerous points.

In carrying the present invention into effect the main lonigtudinal members of the boat structure, such as the keel, the chine and the gunwale, are formed with steel tubes bent to the desired shape. These tubular members are supported temporarily by suitable jigs or forms and the tubular keel l and the tubular chine 2 are connected together by transverse strut bars 3, the ends of said bars being cut on the arc of a circle to t snugly to the circumference of the tubular keel and chine, it being only necessary to cut these strut members different lengths in accordance with their position in the structure.

A preferred form of structure for the struts 3 is that of a light steel T-bar, the web 4 of which is formed with the part circular notched ends 5.

'When these strut bars are inserted between the longitudinal tubular bars with the flange portion resting upon the curved perimeters of the -tubes and the-v notched ends -engaging the tube to the side surfaces of the stem 1 and welded.

The gunwale 9 after being properly shaped is supported in position above the chine and precut lengths of struts I0, similar to the struts 3, are placed in position.

It will be noted that both in the placing of the chine relative to the keel and of the gunwale relative to the chine the notched ends of the struts will t snugly to the circular perimeter of the longitudinal tubes irrespective of the angularity of the struts, consequently fno kspecial fitting will be required vexcept that the struts vbe cut the .proper length.

The struts fitted between the chine and the gunwale are welded into position lin Va fsimilar manner to the bottom struts and where the forward end of the boat is t'o vbe covered -with al decking a centre tube Il secured at .the ,forward end to the stem of the keel is connected with the gunwale by struts I2 similar to the strut-sill) and 3.

.With the .construction describeda very .light and very rigid framework is producedgandonthis A `framework is vplaced thethin steel sheets which are -to formfthe shell. These sheets-Will be laid upon the transversely vextending edges ,of fthe webs of the bottom and sidefstruts .with their-.lon-

gitudinal edges engaging the transversecurva- -ture `.of Athe longitudinal tubesand .thestraight right yan-gularly sheared edges Y rwill thus, .present a V-groove along their .contact iwith the-longitudinal tubes .to accommodate .the welding -metal. yIt will-beiseen that therounded surface of [the tubes form a neat roundedlcorner between the 4plates where such may be desiredsbut of course if lit is .desired Vto -have a sharp .angled corner` along the chineline the shellplates'can be made to extend beyond the curved suraceof .thetubes .so that thesidevandbottom plates willmeet'and the -.meeting edges can bel welded .together land the Aplates themselves can be .welded from the yinside of the structure to the periphery of ethe l tubes.

It will be appreciated.that-the shell platesrcan be cut the required shape lto be-bentfto fit to the Y `frame and to.be welded in position Vwithout requiring .to .be specially formed by dies.

Where the ends of vplates .abut itheyfcanpbe located to .form a seam in Valignment .with -one `of the struts and the abutting edgesfcan belescarfed and the weld canbemade to yunite -the plates securely to the `strutandto be ljoinedtogether in the one operation,y suchfa joint being `illustrated in Figure 7 vof l.the drawings as indicated by thenumeral |73.

In order that the thin sheetmetalgof theshell shall retain `its contours between .the transverse strut members, longitudinalsupportingbars M may .be `arranged at spaced intervals -to extend longitudinally .between adjacent struts, `and where the T-.shaped-strut bars are used .theends i of; the barsv Maregplaced against thehead iianges v withtheir endsV abutting the webs 4 O- Said struts.

These bars can Ibe held inv `spaced -epositionsjby lwood screws l.5,\orvthey mayrbe, secured Aby bolts .lBwhich .may extend through the outer shell..I as

Vdesirable arrangement and they willwbef-Qlset in vany desirable manner from the transversely far ranged bottom. struts, and-such struts- Vmay lfbe .placed as closely togetherras desiredinfany .parh

.ticular -`Dositionof thegboatftosupport the; engine orfani'. Qtherstruturelnfactfas will bar reaclvery strong for comparatively light weight.

`.willgbe simple to manufacture, requiring no spevnumber of spots along their edges tothe inner surface of the shell plate.

A boat hull structure such as described will be It cial machinery or expensive forming tools.

rr-I-he tubular structure can be utilized to ad- Vantage as Aluidcarriers if desired. A keel strucat :points and serve as a bilge conduit and either chine or gunwale structures may be used for conveyin-gfuel from tanks tovenginges.

Al `structure such as described 'Will lend .itself veryreadily -to rthe Yinclusion Iof `fuel Ytanks .as .part

of `.the `structure as they maybe lwelded inposition attached to -the .transverse struts and they will add strength tothe structure.

In the form of .boat v.illustratedin the half section elevation, Figure 9, the series of shaped longitudinal tubes extending `from keel to gunwale are spacedapartby .strut members similar to those described, that .is to say, the struts :are cut to length Vby cutting outapart-circular notch on the end which ts -the vtubular longitudinal members. These, and the number .oflongitudinal tubes are .regulated entirely `by :the .weightand strength ofboat required.

In the use of steel hulls `such as .herein described it will be 'understood that boatscan `be made practically'unsinka-ble by welding. in watertight bulkheads.

It will also be understood that steel ,hulls will withstand heavier impact'shocks than wood hulls and -willlnot be subject to shattering and may be -easily reshaped or repaired if Abent or damaged.

It will also be understood that while .reference has been made herein to' the structure being of steel, where extremely light-weight boats are .required other light-weight metals 4or alloys can be Vused.

.cross `section arranged transversely between said .longitudinal tubes 'lhaving their 'web ends cut to t the perimeter of said tubes with their -ilange ends overlapping and engaging the longitudinal surface .of the tubes,usaid lianges 'and-cut web ends being welded to the perimeter of said ltubes,

.metal sheets welded to said longitudinal tubes and .transverse-struta and means abutting-said struts and .reinforcingfsaid .metal-sheets between said struts.

v2. A metal boat Vhull .comprising continuous longitudinal tubular keel, -chine and gunwale "members,- T-gshaped struts Ahaving .their webends lnctchedtofiit the periphery of the :tubularmembers and to extend therebetween, the flanges of Vsaid :struts: overlapping and :bearing lengthwise REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,805,669 Liamin May 19, 1931 1,810,097 Wheeler June 16, 1931 2,122,300 Smith et al June 28, 1938 2,162,822 Parsons June 20, 1939 2,370,508 Wilkie Feb. 27, 1945 

